OBJECTIVES: 1. To study the effect of masses within the spinal canal and acute spinal cord trauma on spinal blood flow and function. 2. To determine the effects of routine surgical procedures such as laminectomy and durotomy upon spinal cord blood flow in the presence of epidural masses. METHODS EMPLOYED: A technique for percutaneously introducing balloon catheters into the spinal canal was used both to stimulate epidural masses (balloon inflation with slicone) and as a trauma technique (abrupt inflation of large balloon to momentarily impact the cord). Cord function was evaluated by serial clinical follow-up, the motor function of animal being evaluated daily in terms of balance, muscle strength and the ability to walk and climb. In addition, micro-angio-grams of spinal cord blood supply were used to evaluate vascular effects.